PGM and PGM2 don't have many titles because they are IGS products. IGS is a Taiwanese company while most arcade developers are Japanese.

Beware of the KOF98 UM Hero on PGM2, it's a bootleg made by the same Taiwanese team that did KOF 2002 Magic Plus II, KOF 2004 Hero, KOF 2004 Ultra Plus, etc... The only official SNK Playmore releases are KOF 98 UM on Type X and KOF 2002 UM on Y2.